The present invention is related to a plant for decentralized dry cleaning by removing fluorine containing waste gases from the reduction process in electrolytic cells for aluminum.
Known embodiments of plants for dry cleaning of waste gases developed during electrolytic processing of aluminum, are centralized plants servicing one or several halls comprising ovens with cells whereby each hall may comprise between 70 and 150 electrolytic cells or ovens, and which are arranged centrally between the halls or outside. The plant is connected with each of the cells by means of a comprehensive and costly effluent channel. The aluminum oxide used as adsorbent during the cleaning process is stored in separate silos before or after use in the cleaning process and thereafter is transported back to each cell by means of transportation vehicles, cranes or other transportation systems for aluminum, such as a system for transportation in a compact phase.
With the device according to the present invention for cleaning of waste gases from the reduction process of aluminum, substantial savings are achieved as to the volume or area needed, as well as savings in the equipment and time savings during the process and the building. This is achieved with the plant according to the present invention as described with the features stated in the claims.
By using a decentralized plant according to the present invention major parts of the traditional stores and transportation systems for aluminum oxide as can be found in known plants for dry cleaning, are eliminated.
With the present invention a substantial reduction on the space requirement is achieved, furthermore the processing time is reduced and a much more simpler construction and operation is achieved. There is no demand for a storing silo for treated aluminum oxide and likewise the demands for fundamentations are substantially reduced. As opposed to known embodiments of plants, no chimney is required furthermore no silos and no lifting devices. Furthermore large flexibility is achieved as to starting up the operation and there is a short distance between the places for storing of the aluminum oxide and the ovens. The method of storing and the place of storing for the aluminum oxide may be chosen depending on local conditions and suitability. With the present invention suitable groups of between 5 and 40 electrolytic cells may be served in each pant, preferably between 10 and 20.
The present invention provides further substantial reduced energy consumption and thereby achieves substantial cost savings. As a result of the simplified plant, the need for spare parts also is substantially reduced. Outlet dampers for the filters are not necessary and there also is no need for a compressor room as the case is with known plants. The installation time is strongly reduced and the design well adapted for adjustment to specific products.